Weird Vibration!

-
mrtires24

mrtires24

Well-Known Member
Joined
Mar 17, 2008
Messages
1,390
Reaction score
12
Location
Maple Ridge
Ok guys, as some of you may or may not know, I have finished My duster. (are you really ever finished though?)

anyways its a 1970 440 4sp 8 3/4 sure grip. What is happening is if I am cruising down the RD and I put it in nutral, It has a vibration that comes from under the car, You have to be rolling at around 30 miles or more.

The two big parts that I did buy used and put on this car was the 4 spd transmision, and the 323 sure grip pumpkin. I am guessing I have a bad bearing in one of the two, But where and what?

If I am parked and I rev the engine or hold it at an idle it won't do the vibration, regardless of the rpm's I hold it at. It only happens if the car is rolling in newtral, i think I can sometimes feal it when It is in gear two, but I am not sure. You can feal the vibration through your feet on the floor boards near the midle/back of the car ( under front seats, or where you put your feet if you are sitting in the back.

Parts that are NEW are...
Both U joints front and back
axles
axle seals
axle bearings
all the rear brakes
Clutch
preasure plate

I have been told to put the car up on jake stands and drive it with the wheels off the ground and see if I can get it to vibrate. but I won't have time to do that for a couple days, so I thought I would see what you all thought.

I might not be on the computer to answer questions right away either.

Thanks ahead of time. I am sure someone will know what it is :cheers:

Phil
 
Had the same problem with my cuda a while back. Replaced the 4 spd with a 727 and had the drive shaft cut. That was the problem, it was indexed wrong and slightly out of balance. Took it to a machine shop and 100 bucks later it's perfect...no vibration.
 
Robbie2734 said:
Had the same problem with my cuda a while back. Replaced the 4 spd with a 727 and had the drive shaft cut. That was the problem, it was indexed wrong and slightly out of balance. Took it to a machine shop and 100 bucks later it's perfect...no vibration.
Click to expand...

What did you take to the machine shop?

I crawld under the car, and grabed the drive shaft and shook it. There is some play where the yoke slips into the tranny. What bearing or bushing is there? and is it easy to change?

Phil

PS robbie, thanks for the BEll housing...and I'm not guna go to AT, I like the 4 spd.
 
I am not a tec so I am sure some one will jump in here and help you along.

Do you know how a house floor fan runs smooth at low or med, then put it on high and she gets to shaking.:-D
I think when the trans is in neutral the rear tires are spinning your gears and pinion and up tough the drive shaft to the tail shaft of the trans.
I am sure you can have the drive shaft checked for out of balance easy and at a low cost.
I think I would put it up on stands and have someone get the running gear up to 30 or more and look at the area's that could be vibrating.
Remember I am not a tec:stop: so be careful and hope you get this figured out.

Just me, old shade tree man.:read2:
 
Phil I believe Robbie was referring to the driveshaft being his problem. As soon as I was reading your description I was thinking the same thing. It's also possible that it's a tire out of balance.

It sounds like more of an out of balance issue than a bad bearing. Bearings usually howl before they vibrate. Vibrating is the next to the last stage of failure. Last would be locking up or grenading. If it's not howling I doubt it's a bearing.
 
make sure your ujoint on the rearend has the retaining clips on the outside of the caps, mine fell out and i got a wicked vibration.there is a bit of play were the yoke goes into the transmission that is normal. does your driveshaft still have the balancing weight on it? sometimes they come off. you should be able to take the driveshaft in to any machine shop with a lathe to turn it on to see if it is true. good luck and stay with the 4speed ,you will love it.
 
mrtires24 said:
grabed the drive shaft and shook it. There is some play where the yoke slips into the tranny. What bearing or bushing is there? and is it easy to change?
Click to expand...

That could be your problem, there should be minimal slop there. When your'e in neutral & moving it could be bouncing around because there's no load. In the tailshaft there's a coated bushing about 3 inches long that the driveshaft rides on. You have to remove the tailhousing to replace, you need a special tool to install it right. Any trans shop can replace easily, it's the same as those on 727 automatics.
 
Recheck,recheck, recheck the frt U Joint<.... if it's ok. Change the rear bushing in the tail shaft.
 
I pulled the drive shaft Phil. Took it to the machine shop and had it back in 2 days. Some of the drive shafts had weights tacked on and you might have lost one...rusted off or went to lunch..LOL I had a friend shorten it the first time and found out he didn't know alot about how it's done..he is a good welder though.
 
I am leaning more towards somthing in the tail shaft of the tranny. The reason being is that when I arrived home I checked under the car. ( I was away for two days) and there is some fluid that leaked out of the tail shaft. Do you guys know what the name is for that sleave? is it a tail shaft sleave?

Thanks Phil
 
mrtires24 said:
Do you guys know what the name is for that sleave?
Click to expand...
It's the tail shaft bushing, the same part is used on automatics. You will need to remove the tranny & tail housing. You will also need to change the seal. Any decent trans shop should have this bushing. A local shop changed mine for all of $5 (including part!) but $20 is probably more realistic. If left untreated it can destroy the tailhousing, bought a trans for cheap once not knowing it was messed up. Note there are 2 types of bushing, one large (for 727 auto & all big 833) & one small (904 auto, some 3-speed, & some early A-body 833).
 
I phoned the parts store, and they said that there prob is only bearings back there. I don't have a blow up of the tranny to see the part. can anyone send a pic, or a link to where I can see it?

Thanks ahead of time.

Phil
 
396 Signet said:
It's the tail shaft bushing, the same part is used on automatics. You will need to remove the tranny & tail housing. quote]

I can't just remove the tail housing from the tranny? can i do it with the tranny in the car, or do I have to drop the tranny to remove the tail shaft housing. Looks like if I unbolt the tail shaft housing it should just slide off. and the bearing would be in the housing right? then I could take it to a trans shop to change the bushing. am I wrong here?

Phil
Click to expand...
 
mrtires24 said:
396 Signet said:
It's the tail shaft bushing, the same part is used on automatics. You will need to remove the tranny & tail housing. quote]

I can't just remove the tail housing from the tranny? can i do it with the tranny in the car, or do I have to drop the tranny to remove the tail shaft housing. Looks like if I unbolt the tail shaft housing it should just slide off. and the bearing would be in the housing right? then I could take it to a trans shop to change the bushing. am I wrong here?

Phil
Click to expand...
Is there an access door on the side (cover with 2 screws) where a snap ring tool is used ? My memory is gone.
Click to expand...
 
RedFish said:
mrtires24 said:
Is there an access door on the side (cover with 2 screws) where a snap ring tool is used ? My memory is gone.
Click to expand...


I don't know yet, I'm not working on it, I am just trying to figure it out befor I get my hands dirty.

I am mainly asking if I can remove the tail shaft housing while the tranny is in the car...I worded it bad.

Phil
Click to expand...
 
mrtires24 said:
RedFish said:
I am mainly asking if I can remove the tail shaft housing while the tranny is in the car...I worded it bad.

Phil
Click to expand...

Trans must be removed. You remove the bolts that hold the tail housing, then you release a big ring using pliers that fit in a groove, it's released from the top. The tail housing then slides back off the mainshaft. The speedo gear will need to be removed before you do this. Parts you need will be the tailhousing gasket, bushing, & a new seal. Make sure you get a good seal with the rubber boot, lots of parts stores sell a seal without this & if it leaks it will throw gear lube all over your underbody. Call Brewer's or Passon, they both have every 4-speed part you could imagine.
Click to expand...
 
Actually I've rebuilt a bunch of these & my memory must be going too. You can't just remove the trans tail housing. To get at that release ring, you have to do more disassembly. The main gear set with syncros etc. comes out with the tailhousing, only then can you get at the release ring to pull the gearset off. You more or less have to disassemble most of the tranny. Not terribly difficult but this is what you have to do. What you really need is a service manual. Here's a pic of the bushing-
http://www.passionperformance.com/c44.html
 
Phil I can't help you much on a manual trans repair. All my experience is with automatics. The one thing I can maybe help with is a link to a place I buy all my trans. parts that sells the extension housing bushing. This is the one for 727's that 396Signet says will work. Here the link.

http://www.bulkpart.com/Merchant2/m...66&Category_Code=A727bushing&Product_Count=13

BTW: I tried NAPA's website and they must have things screwed up cause it calls it a bearing and shows a picture of a bearing that looks like the extension housing bearing used in 727's. This bearing I'm referring to is located farther forward than the bushing.
 
It sounds much harder than it should be. I have a couple manual 3 spd tannys at home, I unbolted the speedo gear, and the 5 bolts around the tail shaft housing, and the tail shaft housing slid right off with no problem. I don't see why it would be different for a four spd, I should be able to do this while it is in the car. I don't see why I can't. Whats soo different on a 4 spd?
 
mrtires24 said:
should be able to do this while it is in the car. I don't see why I can't.
Click to expand...
Absolutely no way can you do this in car unless you have removable floor pans. As said most of trans has to come apart. Housing will NOT come off by just removing the bolts! Much too much info to list here, you need a service manual or at least a Chilton or similar book. If you get truly desperate can scan some pages.
 
OK, I will prob just switch the tranny with another 4 spd I have in another car for now.
 
Phil I have a 70 Charger/Coronet factory serv. manual and looked in it at the 3 and 4 speed tranny's and it does show being able to remove the tailshaft on the 3 speeds in the vehicle but the 4 spd. tailshaft removal is listed in the "out of vehicle service" section. It's kinda a long explanation of how to do it so I won't write it here but if you want me to I can e-mail it to you. Just PM me with your e-mail address if you want me to.
 
You must log in or register to reply here.
-

Back
Top